A sensor substrate including an insulating substrate composed of a ceramic sintered body, e.g., an aluminum-oxide-based sintered body, and a detection electrode on the surface of the insulating substrate is used as a sensor substrate applied to, for example, a sensor for exhaust gas. For example, changes in the resistance value and/or the current value due to adhesion of a detection target substance contained in the exhaust gas onto the detection electrode are detected, and the content of the detection target substance in the exhaust gas or the like is calculated and detected based on the changes in the resistance value and the current value.
In order to decompose the detection target substance adhering to the detection electrode, wiring including a heater is disposed in the insulating substrate.